The present invention relates to ink jet recording materials (recording materials for ink jet printing).
The ink jet recording method performs recording by causing ink (recording liquid) droplets generated and scattered by various ink-ejecting principles to be at least partially absorbed on a recording material such as a paper sheet. Ink jet recording enables high quality printing or multi-color printing with such advantages as low operating noise and high speed.
Recording inks used for ink jet recording are generally aqueous inks mainly composed of water in view of safety and recording properties. In addition, such recording inks are often added with an agent such as polyhydric alcohols in order to prevent clogging of ink paths and ink nozzles of ink jet printers and to improve the ink ejection stability.
Under these circumstances, most recording materials used for ink jet recording have an ink-receiving layer comprising a water-soluble resin (see, for example, Japanese Patent Application Un-examined Publication Nos. 61-188181 and 3-281384).
On the other hand, recent technical developments have led to wide use of multi-color printing by the ink jet recording technique for the printing of display and presentation materials such as posters and sign boards. When such printed materials are used as open air displays, the ink-receiving layer is particularly required to have water-resistance to an extent that it is not damaged by wind and rain, humidity, or wet or sweaty hands.
However, because most conventional ink jet recording materials comprise a water-soluble resin in their ink-receiving layers as described above, they exhibit poor water resistance.
Therefore, various attempts have been made to improve the water resistance.
For example, Japanese Patent Application Un-examined Publication No. 63-183873 discloses a method for providing an ink-receiving layer comprising a denatured polyvinyl alcohol and a water resistant agent. However, this method has the drawback that ink absorption deteriorates as water resistance improves.
Further, Japanese Patent Application Un-examined Publication No. 59-190885 discloses a recording material whose ink-receiving layer is applied or impregnated with a photo-curable resin after the ink jet printing. However, this material requires troublesome post-treatments, i.e., application or impregnation and curing of the resin.
The present invention has been achieved to solve the problems mentioned above and its object therefore is to provide an ink jet recording material showing excellent water resistance without sacrificing ink-receiving properties and requiring no or only a simple post-treatment.